Most of what we know about the nature of the contraceptive decision-making process in which unmarried, dating couples engage was obtained by analyzing reports from women about their fertility-related beliefs, attitudes, preferences and experiences. However, the growth of the AIDS epidemic has increased awareness that men have an important role in influencing the reproductive health of heterosexual couples. Despite this awareness, there is very little research on the contraceptive and disease prevention choices of couples that is based on data from both partners. In the proposed study, we will address this large research gap. We will accomplish this goal by conducting an in-person survey of approximately 1,200 unmarried, non-cohabiting couples where the female partner is aged 20-35, where neither partner is sterile and where the couple is not currently pregnant or attempting to conceive. An important feature of this survey is that it will build on a similar survey of married and cohabiting couples that began in April 2003, building on its screening effort and sharing many aspects of its design and implementation. This very cost effective survey, in which we will obtain separate, parallel reports from both partners, will provide unique and detailed data on the power relations, perceptions of STD risk, and method-related expectancies, values, perceptions, preferences, and behaviors of men and women making contraceptive and disease prevention choices within the context of an intimate heterosexual relationship. Most importantly, the proposed analysis of these data will allow us to gain new insights into the nature of the contraceptive and disease prevention decision-making process in which couples engage. In particular, it will inform us about how men are involved in that process and how their involvement is related to the types of methods that couples choose, the effectiveness with which they use them, and the specific disease prevention strategies that they adopt. Such information will provide important information that will better enable family planning service providers to help couples achieve their separate and joint reproductive goals and will also aid in designing interventions intended to protect single men and women from the STD/HIV risks.